Technical Field
The present invention relates to nanodevices, and more particularly to devices and methods for stretching biopolymers using nanofluidic channels.
Description of the Related Art
Accurate and inexpensive sensing of biopolymers, especially nucleic acids (DNA, RNA), is important for many scientific and biomedical applications. A high-throughput and robust device to electrically sequence the biopolymers is of great importance. Solid-state bio-sensing techniques, such as artificial nanopores and channels, have been integrated into fluidics for sensing (sequencing) many types of biopolymer molecules, including DNA, RNA, proteins, etc. For precise single molecule sensing of biopolymers, a linearized or fully stretched biopolymer chain conformation is desirable. However, thermodynamically favored conformation of flexible biopolymers, such as a single strain DNA, includes a coiled conformation. One key issue for sensing biopolymers is a large entropic energy barrier for biopolymers (e.g., low entropy for stretched biopolymers and high entropy for coiled ones) to be transported from a large dimension into a smaller dimension. Such a large energy barrier originates from the entropic difference of the flexible polymer.
A large energy barrier greatly lowers the translocation rate of the biopolymers, and can cause very long clogging events in nano-scale channels. Such a large entropy change can cause configurational instabilities of the biopolymers and even drive them to randomly coil and decoil inside the nanofluidic channels or pores. All of these and other problems can lead to reduced and clogged events and thus severely affect proper detection of molecules. Moreover, the entropic energy barrier height increases with the biopolymer chain length, making it very undesirable for precise and high-speed sensing of long biopolymers.